Double acting cold trap

Abstract

A double acting cold trap equipped with a set of exhaust gas condensing fins and a set of exhaust gas condensing plates is disclosed. The invention also discloses a double acting cold trap that incorporates a deflecting plate to direct the exhaust gases over the condensing fins and plates in a serial fashion. This increases the efficiency of the collection of unwanted particles.

What is claimed is:  
     
       1. A double acting cold trap for collecting unwanted byproducts, reactants and particles in the exhaust gases of a low pressure chemical vapor deposition system comprising: 
       a cylindrical stainless steel housing;  
       a gas inlet port on the side of the cylindrical steel housing;  
       a gas outlet port on the bottom of the cylinder; and  
       a gas condensing apparatus with cooling liquid inlet and outlet fittings, condensing fins parallel, and plates perpendicular to the gas flow.  
     
     
       2. The double acting cold trap of  claim 1 , wherein the condensing fins and plates are so arranged as to allow the exhaust gases to first pass over the condensing fins and secondly over the condensing plates. 
     
     
       3. A double acting cold trap with condensing fins and plates so arranged as to maximize the condensing surface area presented to the exhaust gases. 
     
     
       4. The double acting cold trap of  claim 1  wherein said condensing fins and plates are so arranged as to utilize the same cooling liquid input and output fittings. 
     
     
       5. The double acting cold trap of  claim 1  further comprising a deflecting plate that directs the exhaust gas flow over the condensing fins and secondly over the condensing plates, in a serial fashion. 
     
     
       6. The double acting cold trap of  claim 1  wherein said plates incorporate holes so arranged as to allow for free flow of exhaust gases. 
     
     
       7. The double acting cold trap of  claim 6  wherein said plates with holes that are staggered plate to plate so as to maximize the surface area of the condensing plates in contact with the exhaust gases. 
     
     
       8. The double acting cold trap of  claim 1  wherein said gas inlet and outlet ports are arranged at 90° so as to allow for a double set of condensing fins and plates to be arranged in the exhaust gas path. 
     
     
       9. The double acting cold trap of  claim 1  wherein said exhaust gas inlet and outlet ports are arranged at 90° to provide for integration to the overall LPCVD system. 
     
     
       10. The double acting cold plate of  claim 6  wherein said hollow condensing fins and plates provide a closed circuit path for the cooling fluid.